Potential-regulator.



No 876,979. PATENTED JAN.2'1', 190s.

- E; LBHR.

POTENTIAL REGULATOR.

. APPLICATION FILED NOV. 13, 1905.

@ZLWM F WITNESSES: 9

- systems of distribution.

atively inconsiderable in 'nnuntain suitable phase relations between feeder regulation .trical regulation UNITED STATES PATENT :OFFICE. EDWIN LEHR, or WILKINSBURG, PENNSYLVANIA, ASSIGNOR To WESTINGHOUSE ELECTRI MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA.

POTENTIAL-RE GULATO RQ Specification of Letters Patent.-

' Application filed November 13. 1905. samba. 287,168.

Patented Jan. 21, 1908:

To all whom'z't may concern.

Be it known that I, EDWIN LEHR, a citizen volta e winding. f the United States, and a resident of Wilkins- By connecting the series burg, in the county of Allegheny and State of the power transformers, the voltage imof Pennsylvania, have invented. anew and pressed u onthe external circuits is varied useful Improvement in Potential-Regulators, at the wii of the operator and the regulated of which the following is a specification.

My invention relates to systems of electric and "particularly to the r'egulation of three-phase alternating current voltage always remains in phase with the voltage in the secondary winding to which the circuit is connected.

I have provided two series transformers each having two secondary windings in place of the three series transformers of the prior art, regulation being obtained by the use of two auto-transformers and two re 11- lating switches, which obviously simpli ms the system and considerably reduces the amount of auxiliary apparatus employed.

My invention is illustrated in the accompanying drawings, in .which Figure 1 is a diagrammatic view of a system arranged in accordance therwith. Fig. 2-is a similar view of a modified arrangement which may perform the same functions, and Fig.3 is a vector diagram showing the hase relations between the electromotive orces induced in the and 2.

The object of my invention is to provide a system of the aforesaid class that shall'adequately and simultaneously. regulate the 1 potential between lines and that shall pre-l serve the relative phase relations of the l electromotive forces imposed upon the outgoing circuits.

A further object of my invention is to eliminate a' considerable port-ion of the elecapparatus formerly employed in systems of this character.

In three-phase alternating current systems of distribution it has been iound desirable to provide regulation which 1 although. relits range, shall the lines supplied and also simultaneously. T is has been accomplished in the prior art in combination with an ordinary reducing system oftransform ers, which were either delta or star connected in accordance with well known principles. When three transformers were star connected for thispurpose, the outer terminals of their secondary windings were connected to the outgoing circuit conductors through the windings ofseries transformers, these three series transformers being enerl gized by independent primary windings,

which were supplied with variable Voltages that were in phase with the electromotive J forces induced in the secondary windingof )roduce such electrical energy is supplied from a threephase circuit a, I) and c to an outgoing feeder circuit as, 'y and z. Thev primary windings of transformers 1, 2 and 3 are delta connected in the usual manner and are completely insulated from the feeder and regulating systems. The secondary winding 4 of the transformer 1 is connected through a secondary winding 5 of a series transformer 6 to the conductor a; of the feeder circuit. The secondary winding 7 of the transformer 2 is similarly connected through a secondary winding 8 of a series transformer 9 to the conductor 2 of the feeder circuit, while the secondary winding 10 of the tsansformer 3 the power transformer to which the series transformer was connected. Thcse variable voltages were either supplied by auto-transformers which were connected. across each phase of the line and were provided with a plurality of taps, or from the secondar T J winding of the power transformer, in whic 1 5 case this winding was provided witlfnumerf E 11 of the series transformer 6 and a secondary winding 12 of the series transformer 9, connected in sorios, to the feeder conductor 7 A pair of similar auto-transformers 13 and 14 are respectively connected between the outer terminals of the secondary windings 4 and 7 and the neutral conductor 0 of thethree secondary windings 4, 7 and l0, which are Y-connccted. In this way, the neutral point of the distributing system is accessible irrespective of the primary ous intermediate taps, the three voltages being'sinmltaneously varied, by interlocking a plurality of regulator mined the switches which deterconuec'tions between the primary f of the series transformer and the variable trans ormers in this way to the secondaries various windings of Figs. 1

is connected, through a secondary winding 10.0

switches 17 and 18, since the electromotive forces impressed upon the conductors a;

and z of the feeder circuits are obviously in phase with the electromotive forces ill. duced in the secondary windings a and 7, while the elcctromotive force impressed upon the feeder conductor 3 is substantially in phase with the electroinotive force induced in the secondary'winding 1.0, since the resultant of the component clectrt motive forces which, are induced in the windings 11 and 12 of the series trahsformers 6 and "motive forces induced in the secondary I Fig.

winding 10.

In order to demonstrate the relations above specified, reference may be had to 3, in which the elcctromotive force vectors are shown in their existing relations,

vector 6* representing the electromotive force induced in the secondary winding 4 and electromotive force vectors c and 6 representing, respectively,- the electrometive forces which are induced in the secondary windings 10 and 7. The elcctromotive force 1! induced in the secondary winding 5 of the series transfori'ner 6 is added to the electromotive force induced in the secondary winding 4 and is in phase therewith, since this series transformeris energized from the auto-transformer 13, which is energized directly from the secondary winding 4. The voltage induced in the winding 8 of the series transformer 6, which is represented by e in the vector diagram, is added to and is in hase with the electromotive force e which 1s induced in the winding 7 for the same reason. Vector e is shown parallel to the vectors c and e and represents the voltage induced in the winding 11 of the series transformer 6, which is added to theelectromotivc force induced in the secondary winding 10. Line 0 is drawn parallel to the vectors e and e and represents the voltage induced in the winding 12 of the series transformer 9, which is added to the electromotive force represent ed by e and 6 Since the supply circuit a, b and c is a three-phase circuit, the vectors e", e and e will be one hundred and twenty degrees apart, and consequently the result- The 1 is insured by interlocking the regulator:

9 is in phase with the electrol l l l l l l l l l l l l 1 a, l l l l l l l l l, l

.srae'ze equal to these vectors and form an equilateral triangle therewith, and since vectors a and e are respectively parallel to the vectors 6" and'e the resultant 0 will form a continuation-of the vector c Referring to big. 2, in which similar nu morals refer to the same partsas in Fig.1, the outer terminals of the secondary windings l, 7 and it) are respectively co "ect-ed directly to the feeder circuit conduct regulation in this instance through series 'trans'f 'rmers 6 and 9, the secondary windings of which are respectively connected between the inner terminals of the secondaries 4r, 7 and 10 and the neutral conductor o in, 1

being obtained for this purpose that are connected to con-' tact terminals 21 and :22 which are engaged by mechanically interloidring contact arms 19 and 2a The simultaneous regulation of the clectromotive forces and their proper phase relations are secured in this in pro ceding instance.

it will be seen that many variations. in the circuit connections may he made without dearting materially from my invention, and I desire that such variations shall be included in its scope.

l claim as my invention: 5 c. his

1. The combination with a three-phase alternating current source of electrical energy and three transformers having their primary windings connected thereto and their secondary windings Y-connected to a supply line, of a pair of series transformers each having a primary winding and two secondary wind ingsarrangcd and connected to preserve the neutral point of the system and to. give simultaneous potential regulation between the several supply lines.

2. The combination with a, three-phase alternating current feeder system, of means for regulating the voltage between lines that comprises a pair of series transformers and means for simultaneously regulating the exciting voltages applied thereto.

3, The combination with a three-phaso alternating current feeder system, of two series transformer and two regulating switches for simultaneously regulating the voltage between the lines.

4'. The combination with three power transformer secondary windings, one terminal of each of which is connected to a supply line, two series transformer" econdary windings connected to corresponding terminals of two of the powerwindings, and two secondary windings for sr d series transformers connected in series with each other s :0, 'y and 2,

' free terminal of means for simultaneously varying the excit- 1 supply line conductor,

. Emma to the free terminal of thepower transformer, of means for simultaneouslv varying the} exciting voltage applied to said seriesjtrans formers; j

5. The combination transformer secondary windings, one -termi nal ofeach of which is connected'to a-s'upplly f hne, two series transformer secondary win ings connected to corresponding terminals of two of the power windings; and two secondary windings for said connected in series with each other to the the power transformer, of

ing voltage applied to said seriestransfo'l' ers, said means comprising exciting windings therefor, auto-transformers having intermediate taps, and switches forconnecting said taps to said exciting windings.

6. The combination with three Y-connected transformer windings, I auto-trans formers connected between the outer terminals and the common terminal of transformer windings, and two formers having-secondary windings connected to corresponding terminals of the auto transformers and to a pair of supply line conductors, and secondarywindings connected, in series, to the free power transformer winding terminal and to ductor, of means for varying the exciting voltageapplied to the series transformers.

7. The combination with three Y connect ed power transformer windings, auto-transformers connected between two outer terminals and the common terminalof said power transformer windings,

formers having secondary windings connectand two series transed togcorresponding terminals of the auto.- transformers and to 'a )air of supply line conductors, and secon ary windings connected, in series, to the free power transformer winding terminal and' to a third of means the exciting voltage applied tothe series transfori'ners, said means comprising exciting windings therefor which are supplied with variable voltages from said auto-transformers.

8. .The combination with three Y-connected power transformer windings, auto-transformers connected between two outertennis hide and the common terminal of said power transformer windings, and two series transformers having secondary windings con nected to. corresponding terminals of the auto-transformers and to a pair of supply line conductors, and secondary windings connected, in series, to the freepower transformer winding terminal and to a third sup- ,ply line ondary windings, voltage of the three lines simultaneously and for maintaining the proper phase relation between said voltage's, said means comprising said power series transe a third supply line conrate exciting and switchesfor varying the voltages supfor varying conductor, of switches cooperating with said auto-transformers for simultaneous'ly varying the exciting voltages applied 7 "to the series transf with three I power 9. The combination with three i-connecte' ed power transformer windings, auto-trans orme'rsconnected between two of the outer terminals and the common terminal of said windings, and two series transformers having primary windings that are energized from said auto transformers ary windings which are connected in series andto the free terminal of the power trans; former. v

19. In a three-phase feeder system, the combination with three wire transfdTmerscof means for ,varying'; the

two interlocked. regulator switches and two series transformer and having second- I1. In a three-phase feeder system, the

combination with three wire transformer secondary windings, ofnieans for varying the voltage of the three lines simultaneously and for maintaining the proper phase relation between said voltages said means comprising two'series'transformers having sepacoils, -tw0 auto-transformers,

plied thereby. v

12.,The combination with a three-phase power circuit; threefgprimary transformer.

windings severally connected to said circuit conductors and interconnected at their opposite ends, three interconnected secondary windings, auto-transformers connected be tween two outer terminals of the secondary windings and their'common terminals, two

.series transformers havin prima ry windings b which areenergized from sa1dauto-transformers and two secondary windings one of each of which is connected'in seriesbetween the outer terminal of one of 'said interconnected second arywindings and a feeder circuit and one secondary of. each being connected respectively to the remaining two outer ter-v minals of the interconnected secondary windings, of means for simultaneously varying the eiectromotive force impressed upon the primaries of said series transformers.

In testimony whereof, I have hereunto subscribed my name this '9th' day ofNovember,

' EDWIN LEHR. Witnesses HENRY D. JAMEs, Bmxnr HINEs. 

